Inundation model of Ixtapa-Zihuatanejo zone produced by an hypothetical local tsunami generated by an earthquake of 7.0 on the Richter magnitude scale

Abstract:

Possible flooding coastal areas in Ixtapa-Zihuatanejo, Guerrero were obtained by a numerical model, the initial condition was a hypothetical local tsunami generated in the Cocos Plate by an earthquake of 7.0 on the Richter magnitude scale, resultant on a wave with an initial amplitude of 1.5 m.

Based on the results it can be concluded that Ixtapa presents the maximum height of the inundation wave; it takes 17 min and 40 s to the tsunami wave to reach the coast and 18 min to the highest one that has an approximate height of 4 m; the flood zones reach a maximum of 4.5 m of high and get 276 m inland.

The potentially dangerous zones are the hotel zone located next to the beach and La Marina Ixtapa, distant of the most populated areas. In Zihuatanejo the hypothetical tsunami wave takes 19 min to reach the coast, the maximum height at the coast is also presented after 20 min of the start and has an approximate height of 2 m. It can be observed that the bay has an attenuation effect of the tsunami wave causing minor inundation areas and a maximum height of 3 m, with a penetration of 168.5 m inland. The potentially dangerous areas are shopping areas near to the beach away from hospitals, local markets and highly populated areas.

The main advantage of the hydrodynamic model used over others is that it allows to model the flood inland of the tsunami compared with another models that only model the propagation of the tsunami wave and the final results are the height of the waves when reaching the coast, without estimating the flood zones.